The traditional technique employed to train artillery and mortar crews involves stationing an observer in a protected position, well forward of the firing battery. This forward observer is advantageously located in a position from which he can view the entire target area and report back by radio or field telephone the success or failure of each round that is fired. To assist the observer, all larger caliber training rounds, including artillery and mortar rounds ranging from 40 millimeters to 8 inches, have a point-detonating fuse located in the nose of the projectile. This fuse comprises a standardized charge that produces a brilliant flash of light, a loud report, and a puff of smoke upon impact. Obviously, the purpose of this charge is to enable the forward observer to observe and report back to the firing battery the approximate impact point of the projectile.
Even though such training rounds carry no high explosives, they, nevertheless constitute a very real hazard and the forward observer cannot be located too close to the target. Thus as a practical matter, due to the remoteness of the observer some inaccuracies as in target scoring must be expected. This problem is compounded when the projectiles to be scored comprise ground-to-ground, air-to-air, air-to-ground, and ground-to-air missiles and rockets, due to the much greater risk involved.
Various attempts have been made to overcome this problem. For example, one proposed system involves tracking the projectile to the target by radar. It will be apparent, however, that such a system is expensive and very complex. Worse, it usually requires specially modified training rounds and firing tactics.
Another proposed system utilizes a target comprising a spatial, geometric pattern of laser diodes. Any projectile entering the target area is required to have a retro-reflector fitted thereto so that, as the projectile enters the target area, it interrupts one or more of the laser beams and produces a signal on the corresponding light sensors. Again, specially modified training rounds must be employed.
Yet another proposed system employs a re-radiating microwave transmitter on each projectile. Once again, specially modified ammunition is required. High-speed motion picture photography and closed-circuit television have also been used to detect and score artillery training practice.
All of the above-described systems suffer from the disadvantage of an extremely high system cost and/or the fact that modification of the projectile and fuse, and in some cases changes in personnel training tactics, are required. Since personnel training occupies a considerable time, and large quantities of ammunition, all of the prior art approaches discussed above are either restrictive or undesirable. As a result, it has become clear that a new technique for target scoring that avoids the shortcomings of the prior art is very much in demand.